OBJECTIVES: 1) We will complete studies of protein-supplemented modified fasting with and without addition of carbohydrate to compare the effect on the capacity for endurance exercise of varying severity, on endocrine and substrate responses, on appetite and affect, and on the maintenance of serum retinol-binding protein and thyroxine-binding pre-albumin. 2) We will explore the effect of physical training in the course of rapid weight reduction in non-insulin-dependent diabetic patients (Type II) with respect to insulin resistance, measured by the glucose clamp technique, body composition, thermogenesis, thyroid and catecholamine response. 3) To define more optimal methods of achieving maintenance of weight after loss by diabetic overweight subjects, we will study the effect of gradual stepwise refeeding of calories and carbohydrate with and without carbohydrate and with and without added physical training. The return of insulin in resistance and the changes in thermogenesis, thyroid and catecholamine response, and in body composition will be measured.